Electrical connection.



No. 774,202. PATENTED NOV, 8,1904.

F. J. RUSSELL- ELECTRICAL CONNECTION.

APPLIOATION FILED JAN. '1, 1904. no MODEL. QSHEETS-SHEET 1.

9 HI? cz Fl m I, m

IHII[ N gmm A 8 o gijxxxmixzim PATENTED NOV. 8, 1904.

F. J. RUSSELL.

ELEOTRIOAL CONNECTION.

APPLICATION FILED JAN. 7, 1904.

N0 MODEL 2 SHEETS-SHEET 2.

ZP :P;2.3.2... 1-5. I 1

UNTTED STATES Patented November 8, 1904.

PATENT QEETCE.

ELECTRICAL CONNECTION.

SPECIFICATION forming part of Letters Patent No. 774,202, dated November 8, 1904. Application filed January 7,1904. Serial No. 188,027. (No model.)

To all whmn it may concern.-

Be it known that I, FRANK J. RUSSELL, a citizen of the United States, residing in the city of New York, borough of Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in Electrical Connections, of which the following is a specification, sufficient to enable others skilled in the art to which the invention appertains to make and use the same.

My invention relates to electric-circuitterminal receptacles and extension circuit-plugs generally, although herein shown as adapted particularly for floor or stage use, where special precautions in the line of safety are desirable, for the reason that such receptacles are under foot more or less, and when the plugs are out, as they are normally in most cases, are exposed to the intrusion, either accidentally or otherwise, of foreign objects. For this reason it is desirable to exclude all live terminals and all electrical contact-surfaces from the plug opening or throat of the receptacle and to provide for the automatic discharge therefrom, as far as possible, of foreign objects introduced into the throat by forming the latter in such manner that such foreign objects will ordinarily drop through if smaller in cross-section thanthe extension circuitplug, or if they should lodgein the throat temporarily would do no harm, sincethe lineterminals are inaccessible, the intruding objects being eventually forced out of the throat by the insertion of the plug, unless larger than the latter in cross-section, in which case they can be withdrawn from above preparatory to the insertion of the plug. Another reason whyI isolate the line-terminals and all electrical contact-surfaces within the body of the receptacle and render them inaccessible within or through the throat, except by means of my special form of extension circuit-plug, is to protect them not only from metallic objects the presence of which might result in short-circuiting, but also to prevent access thereto of water, paint, or other liquid or semiliquid substances which frequently find their way from various causes, especially in stage-outlets, into the throat and which if interposed between the line-terminal contactsurfaces and the extension circuit-plug contact-surfaces would result in imperfect electrical connection and undue and possible dangerous heating of the parts. Furthermore, it is very desirable that the contact-surfaces of the plug itself be fully protected and shielded from contact with extraneous objects when the plug is out of the terminal-box in order to keep clean and smooth and in condition for perfect electrical contact with line-terminal contacts, and this I accomplish by insuring their retention within the plug when the latter is Withdrawn from the terminal-receptacle. Again, it is important to effect a sudden break of contact between the electrical terminals in the receptacle and the contact-surfaces on the plug in order to avoid are or sparking and to insure this quick break independent of the will or care of the operator. These desirable results and others hereinafter described I attain by my invention, which con sists, primarily and essentially, in the use in conjunction of the following instrumentalities, namely: a terminal-receptacle in which the terminal-contacts are isolated and away from the plug opening or throat, which latter is practically free and unobstructed, an extension circuit-plug fitting in said receptacle and provided with pivoted contact-arms adapted to be actuated laterally to make and break contact with the live terminals in the receptacle, and fulcrum-abutments within the receptacle arranged toautomatically actuate said contact-arms as the plug is inserted or withdrawn from the throat of the receptacle, substantially as hereinafter set forth.

My invention also includes certain other features in the construction and arrangement of parts hereinafter described and claimed specitically. p

In the accompanying drawings, Figure l is an elevation of one of my improved terminalreceptacles attached to a floor-plate; Fig. 2, an end elevation of the terminal-box with the floor-plate in section. Fig. 3 is a transverse section upon plane of line 3 3, Fig. 1; Fig. 4:, an elevation of the inside of one half of the terminal-box; Fig. 5, an exterior view of one half of the terminal-box. gig. 6 is an elevation of one edge of the exten ion circuit-plug;

Fig. 7, a side elevation of the same; Fig. 8, a transverse section upon plane of line 8 8, Fig. 7. Figs. 9, 10, and 11 are detail views of the extension-terminals used in the plug and to which the contact-arms are pivoted. Fig. 12 is a diagram illustrating the operation of breaking. Fig. 13 is an elevation of the inner side of one of the halves of the terminal-box, showing the line-terminals and fulcrum-abutments in position. Fig. 1 1 is a similar view showing the extension circuit-plug partly inserted. Fig. 15 is a similar view showing the extension circuit-plug fully inserted. Fig. 16 is a top view of the terminalbox without the plug, partly in section. Fig. 17 is a bottom view of the same. Fig. 18 is a sectional view through the terminal-box, taken on plane of line 15 15, Fig. 15. Fig. 19 is a sectional view taken upon plane of line 19 19, Fig. 13. Fig. 20 is a section of the lower part of the extension circuit-plug, taken on plane of line 20 20, Fig. 7. Fig. 21 is an end view of the extension-plug.

The main portion of the receptacle or box 1 B is formed of two plates or halves B B which are made of porcelain or other insulating material and are essentially reversed duplicates of each other except that one is formed with a central vertical groove bfor the reception of a longitudinal bead or projection 9 upon one edge of the extension circuit-plug P, the bead being designed to prevent reversing of the plug when it is inserted in the throat b of the terminal-receptacle B.

The two plates B B are clamped together by any suitable means, as by screws and nuts a a, (see Fig. 16,) any desired number being used to hold the halves of the box rigidly in position.

WVashers w 20 are preferably interposed between the opposed cheek-pieces 7) on the plates B B when the latter are made in porcelain for the purpose of avoiding the strain of a broad bearing, which might be disastrous to that material under excessive strain. These washers and the make fulcrum-abutments F afford the only actual points of contact between the plates B B Opposed central grooves or recesses b and 6 formed, respectively, in the plates B and B constitute the plug opening or throat b of the receptacle, which throat Z) is preferably of uniform area in cross-section throughout, although not necessarily so, the main requisite of structure in this construction being that the throat shall in no part be less in cross-section than its mouth at the top of the box, so that there shall be no contraction of the passage downward. This is for the purpose of allowing foreign objects dropped into the throat to pass through the same and out at the bottom if they are smaller in cross-section than the throat 6, which, it will be seen, is practically free and unobstructed from top to bottom when the plug P is out except for the slight protrusion of ends of the fulcrumabutments F F on either side of the throat 7). Since the break fulcrum abutments F yield and recede from the throat under pressure, the ends of the make-fulcrums F are the only positive intrusions into the throat area, and these are comparatively slight, so that under ordinary conditions even if a foreign object should lodge temporarily within the throat the insertion of the circuit extension-plug P would force it down and out at the bottom.

The receptacle as a whole is secured to a suitable floor-plate C by any well-known mechanical expedient, as by stirrup-straps c 0, secured by screws 0 0 to the under side of the plate C, which latter is formed with an opening 0 coinciding with the mouth of the throat b, in the receptacle B underneath.

In the side recesses 6 6'', formed between the plates B B upon opposite sides of the throat I) and underneath the cheek-pieces Z) 6 are secured the terminal contacts T T for the line-wires If If. These are not necessarily limited to the construction shown, since other forms of spring-jaws may be used as terminals; but I prefer this construction as affording a high degree of elasticity and resilience, which insures an intimate electrical contact with the surfaces Z Z on the contact-levers L L. carried pivotally upon the extension circuit-plug P. This preferred form of main terminal contact T consists of a piece of sheet metal bent to form the post 23 for the reception of the binding-screw 15 with two side members or limbs 25 t the ends of which are turned inward to form the actual contact-surfaces t 6*, as will be understood by reference to Figs. 18 and 19. The terminals T are each held in position between the opposed surfaces 7/ b of the plates 13 B by certain of the screwbolts (0, which pass through the side members 25 6 A screw-stop G is provided in each terminal T to gage the upward thrust of the contact-levers L.

The faces of the make fulcrum-abutments F adjoining the throat b are formed with ribs f of a width not greater than that of the contact-levers L, and the upper ends of said fulcrum-abutments are wedge-shaped, converging toward the points of the ribs f.

The break fulcrum-abutments F are pivotally supported between the plates B B and are provided with springs f, which tend constantly to throw their lower ends out into the throat b, a tendency which is counteracted by the contact of their upper ends f with the sides of the receptacle. The lower. ends of the break fulcrum abutments F are thus thrust out into the throat normally, mainly for the purpose of protecting the pointed wedge-shaped upper ends of the make fulcrum-abutments F from contact with foreign objects dropped or thrust into the throat, since the said lower ends of the break fulcrum- ITO abutments would thus obviously act as deflectors to guide articles toward the center of the throat and hence away from the wedge-shaped ends of the make fulcrum-abutments.

The extension circuit-plug P consists of a body 2 of non-conducting material, in which are embedded and secured metallic terminal hinge-plates q q, to which the extension circuit-wires e c are connected by suitable binderse' e. To these metallic terminal hingeplates 11 g are pivotally secured the contactlevers L L, the body of the plug P being formed with side recesses 19 p for their reception when closed, in which position they do not preferably protrude beyond the exterior surface of the plug. The lower portions of the circuit-levers may be slit longitudinally, as shown in the drawings, if desired, to increase their lateral elasticity, although this is not essential. Their lower or outer ends are beveled to facilitate engagement with the beveled ends of the make fulcrum-abutments F. l/Vhile the slitting of the lower portions of the levers L L longitudinally, as above named, is optional, I intentionally slit and slightly spread their upper portions adjacent to the pivots to create sufiicient frictional contact with the hinge-platesq q to insure the retention of the levers L L within the side recesses 10 after the plug is withdrawn from the throat of the terminal-box. This not only prevents the levers from doing injury or being injured if slung around carelessly, as is apt to be the case, but also keeps their electrical contact-surfaces clean and unimpaired.

In use the parts operate as follows: As before intimated, when the plug is out of the throat the downward protrusion of the flexible break fulcrum-abutments F into the said channel protects the rigid points of the make fulcrum-abutments from contact with foreign objects by deflecting such objects therefrom toward the center of the throat. Even should metallic substances be intruded into the throat and even though they lodge there temporarily they can do no harm, since there are no live parts protruding into or accessible from the throat, the line-terminals'TT being practically inaccessible except to the swinging contact-levers of the plug P. Hence short-circuiting between the two said line-terminalsT T is impossible and all danger on that score is avoided. lVhen the plug is inserted into the throat 6, it first deflects the lower ends of the break fulcrum-abutments inward. Its continued depression brings the pointed ends of the make fulcrum-abutments F underneath the lowered beveled ends of the contact-levers L L, as shown in Fig. 14, and then springs said outer ends into contact with the line-terminals T T, the points of the make-abutments F acting as fulcrums upon which the arms L L, as levers of the first order, turn to throw their contact surfaces ZZ in between the contact-surfaces t t of the line-terminals TT. This action, owing to the thrust imparted to the I plug, is comparatively rapid. the make being almost instantaneous, and hence correct from an electrical point of view; but while it is desirable to effect the make-contact quickly it is doubly important that the break should be effected instantaneously, or as nearly so as possible, in order to avoid arcing, &c. This 1 accomplish positively and automatically and irrespective of the care or'attention bestowed by the operator by the use of the break fulcrum-abutments F, which as the plug is withdrawn suddenly encounters and throws the levers L Loutof engagement with the contactsurfaces t t of the line-terminals T T. This will be understood more readily by reference to the diagram, Fig. 12, by which it will be seen that after a lever comes in contact with the lower end of a break contact-abutment F an extent of continued upward movement equivalent to approximately one half the thickness of a lever is sufiicient to separate the contact-surfaces of the lever from those of the line-terminals, the inertia acquired by the plug in the operation of starting it upward overcoming the resistance encountered by reason of contact with the abutment and quickly carrying the pivot of the lever above the lowerends ofv the fulcrum. It is obvious that in the fraction of time in which the pivot and short arm of the lever thus passes above the lower end of the break-fulcrum the outer or long arm of the lever will be forced down ward at a speed proportionate to its length from the break-fulcrum, and consequently the electrical contact-surfaces Z Z practically instantaneously withdraw from the contact-surfaces Z of the line-terminals T T, thus avoiding all possibility of the continuation of an electric arc, with its attendant dangers. It is practically impossible to remove the plug slowly enough at the breaking contact to cause arcing, since the springs clutch the plug-arms and retard the withdrawal of the plug until sufiicient force is applied to overcome such resistance, when the plug leaves the contactsprings with a jerk or sudden deflection downward that insures a practically instantaneous separation of the parts. In this connection it is to be noted that the lower extremities of the line-terminals T are inclined at an angle which facilitates this quick break of contact between them and the levers L.

The break-abutments F are free to yield and adapt themselves to the changes in position assumed by the levers L while the plug is being withdrawn from the throat Z.

The withdrawal of the plug P from the throat Z forces the contact-levers within the side grooves of the plug, in which position their contact-surfaces Z Z are isolated and protected from contact with extraneous objects, as well as from dirt, the levers being held in position in the grooves by frictional contact with the hinge-plates, as hereinbefore stated. The upper portion of the plug and the exten sion circuit-terminals may be protected as heretofore with a sleeve S; but this feature forms no part of my invention.

As hereinbefore intimated, I do not limit my invention to a floor or stage outlet, since it is obvious that the essential features of my device may be used as a wall or ceiling terminal or outlet, the main difl'erence between such terminals and the floor or stage terminal box being ordinarily one of size only.

Hence what I claim, and desire to secure by Letters Patent, is

1. The combination of an electric-terminal receptacle having line-terminal contacts situated upon opposite sides of its plug opening or throat, make and break fulcrum abutments, an extension circuit-plug formed with pivoted contact-levers capable of lateral deflection by contact with the outer abutments, and instrumentalities within the said terminal receptacle arranged to automatically force said pivoted contact-levers carried by the plug into and out of engagement with the line-terminal contacts in the receptacle when the plug is inserted into or withdrawn from the throat of the same.

2. The combination of an electric-terminal receptacle having line-terminal contacts upon opposite sides of the opening or throat for the reception of the extension circuit-plug said line-terminal contacts being situated entirely beyond the said throat soas to leave the latter practically free and unobstructed and without live electric surfaces exposed therein, said extension circuit-plug formed with pivoted contact-levers capable of lateral deflection, and instrumentalities within the said terminal receptacle arranged to automatically force said pivoted contact-levers on the plug into and out of engagement with the line-terminal contacts in the receptacle when the plug is inserted into or withdrawn from the throat of the same.

3. The combination of an electric-terminal receptacle having line-terminal contacts situated upon. opposite sides of and beyond an extension circuit-plug opening or throat which has no live electric surfaces exposed therein, an extension circuit-plug formed with pivoted contact-levers capable of lateral deflection, make fulcrum-abutments situated at the sides of said throat and arranged to engage the said pivoted contactlevers and deflect them into engagement with the said line-terminals beyond the throat, and break fulcrurn-abutments situated at the side of said throat and arranged to engage the said pivoted contact-levers and throw them out of engagement with the said line-terminal contacts.

f. An electric-terminal receptacle having the line-terminal contacts arranged internally and entirely removed from the extension-plug throat which extends entirely through the receptacle without contraction from the size of the mouth-opening to its other open end, an extension circuit-plug insertible within said throat and. formed with pivoted contact-levers capable of lateral deflection, and instrumentalities within the said terminal-receptacle arranged to automatically force said pivoted contact-levers on the plug into and out of engagement with the line-terminal contacts in the receptacle when the plug is inserted into or withdrawn from the throat of the same.

5. The combination of an electric-terminal receptacle having line-terminals situated upon opposite sides of and beyond an extensionplug opening or throat having no live electrical surfaces exposed therein, said throat being formed with a longitudinal groove on one side thereof, an extension-plug formed with a longitudinal bead fitting in said longitudinal groove in the throat, and provided with pivoted contact-levers capable of lateral deflection, make fulcrum-abutments situated at the sides of said throat and arranged to engage the said pivoted contact-levers and deflect them into engagement with the said line-terminals beyond the throat, and break fulcrum-abutments situated at the side of said throat and arranged to engage the said pivoted contact-levers and throw them out of engagement with the said line-terminal contacts.

6. The combination of an electric-terminal receptacle having a threat or opening for the reception of an extension circuitplug, said. throat being formed with a longitudinal groove in one side only, and an extension circuit-plug formed with a rib, or projection on one side only fitting into said longitudinal groove in the throat of the receptacle for the purpose of preventing reversal of the plug as it is inserted in said throat, as set forth.

7. The combination of an electric-terminal receptacle having line-terminal contacts situated on opposite sides of and beyond an extension circuit-plug opening or throat therein and insulated from the exposed inner surface of said opening or throat, an extension circuit-plug formed with pivoted contact-le- 'ers capable of lateral deflection, make fulcrumabutments situated at the sides of the throat and arranged to engage the said pivoted contact-levers and deflect them into engagement with the said line-terminals beyond the throat, and break fulcrum-abutments situated at the side of the said throat, and arranged to engage the said pivoted contactlevers and throw them out of engagement with the said line terminal contacts, the said break fulcrum-abutments being pivotally supported within the receptacle and being provided with springs which tend constantly to hold them in their normal position, for the purpose set forth.

8. The combination of an electric-terminal receptacle having line-terminal contacts situated on opposite sides of and beyond the circuit-plug opening or throat an extension circuit-plug formed with pivoted contact-levers capable of lateral deflection and with longitudinal recesses in which the said contactlevers fit, the inner or pivotal ends of said contactlevers being split to create suflicient frictional contact with their hinge-plates to retain the levers in said recesses until forcibly removed therefrom, make fulcrum-abutments situated at the sides of the said throat and arranged to engage the said pivoted contact-levers and deflect them into engagement With the said line-terminals beyond the throat, and break fulcrum-abutments situated at the sides of the said throat and arranged to engage the said pivoted contact-levers and throw them out of engagement with the said lineterminal contacts.

9. The combination of an electrical-terminal receptacle having line-terminal contacts therein upon opposite sides of the plug opening or throat, an extension circuit-plug, pivoted contact-levers thereon, positive obstructions into the throat area, and yielding obstructions adapted to be moved aside by the plug as it is inserted into the throat. Y

10. The combination of an electrical-terminal receptacle, having line-terminal contacts therein upon opposite sides of the plug opening or throat, an extension circuit-plug, pivoted contact-levers carried thereby, positive obstructions into the throat area, and yielding obstructions adapted to be moved aside by the plug as it is inserted into the throat, said positive obstructions being formed with ribs on their inner faces.

11. The combination of an electrical-terminal receptacle having line-terminal contacts therein on opposite sides of the plug opening or throat, an extension circuit-plug having pivoted contact-levers, positive obstructions into the throat area, and yielding obstructions adapted to be moved aside by the contact of the plug as it is inserted, said positive obstructions having their upper ends Wedge-shaped and provided upon their inner faces with ribs.

12. The combination with an electrical-terminal receptacle having line-terminal contacts therein on opposite sides of the plug opening or throat, of an extension circuit-plug having pivoted contact-levers, positive obstructions into the throat area having Wedge-shaped upper ends and ribs upon their inner faces, yielding obstructions adapted to be moved aside by the plug as it is inserted into the throat, and means for normally forcing the lower ends of the movable obstructions out into the throat to protect the Wedge-points of the positive obstructions.

FRANK J. RUSSELL. 

